We wish to obtain equipment enabling us to employ the "2-slit densitometric" technique for measuring on-line volume flow and hence for calculating shear rate in the microcirculation. This will enable us to monitor platelet aggregation in injured microvessels of diabetic and control animals, in vessels selected to have comparable flow and/or shear rates. This will eliminate one source of within-group variability with respect to parameters reflecting platelet aggregability in vivo and will permit us to more readily demonstrate differences between diabetic and normal animals, if such exist, as well as demonstrate effects on these differences.